1. Field of the Invention
This invention relates to a hole punching apparatus of the type normally associated with a printing operation involving web fed paper, with the apparatus hereof being designed for selective operation whereby the operator can easily and quickly change from one hole punch pattern to a different hole pattern, thus substantially reducing makeready times and the attendant costs. More particularly, it is associated with a punch ring apparatus having a plurality of radially-oriented, spaced-apart punches shiftably mounted in the punch ring whereby the punches can be selectively positioned for punching or retracted into an inoperative position according to the hole pattern desired.
2. Description of the Prior Art
Many different types of punching units have been utilized in the past in the printing industry for punching holes in a continuously moving web of paper. Such punching units, have typically been incorporated as a modular unit in the bindery section of a printing operation, or alternatively, incorporated into a separate bindery unit. Such punch units are designed with the capability of punch file holes, line holes, or special patterns. The file hole punch is typically used for widely spaced holes, with a variety of hole sizes being available. For example, a typical loose leaf might include three relatively large widely spaced-apart holes. The line hole punch is for a continuous stream of closely spaced holes along the marginal edges of the moving web, particularly useful for providing a means for engaging the web with a driving sprocket, etc. As can be appreciated, a variety of hole patterns in a moving web may be called for, depending on the particular job requirements.
Such past punch units have typically included a pair of drive shafts mounted on either side of the web path of travel with a punch ring mounted on the uppermost shaft and a die ring mounted on the lowermost shaft in general vertical alignment relative to the horizontally moving web. Depending on the hole pattern desired, a coordinated pair of punch and die rings would be mounted on the respective shafts. That is, if line holes were desired, a line hole punch ring would be mounted on the uppermost shaft and a line hole die ring would be mounted on the lowermost shaft, with the rings aligned relative to the web for the proper positioning of the holes. The rings are typically split into two halves, such that when they are joined together about the shaft each ring presents a circular in cross-section roller arrangement with the web passing through the nip between the two circular rings. The die ring of such an arrangement presents a plurality of circumferentially spaced-apart, radially-oriented, dies secured in the die ring around the outer periphery. The punch ring includes a plurality of circumferentially spaced-apart, radially oriented bores with the die ring and punch ring positioned on their respective shafts such that when the shafts are rotated, the bores and the dies will vertically align themselves when passing through the nip between the two rings. Elongated punches are then inserted in the bores of the punch ring according the hole pattern desired. Thus, in operation, the moving web travels through the nip between the two rings and the rings rotate such that the punches shear through the paper into an aligned die creating the desired holes in the web.
A number of problems exist with such past punching operations, the most noteworthy being the significant amount of makeready time associated with setting up such punch and die rings. As can be appreciated, a significant amount of setup time is required to set up the punch unit for a different hole pattern. Thus, if it is desired to change over from a line hole operation to a file hole operation, the operator must first remove the line hole punch ring and the line hole die ring, and then install a file hole punch ring and a file hole die ring. Such installation includes vertically aligning the rings, inserting the punches in the bores of the punch ring according to the desired pattern, properly seating the punches in the respective dies, and finally threading the web through the nip to begin operation.
As those skilled in the art will appreciate, the makeready time associated with setup for a different hole pattern can be significant and expensive. Particularly for commonly used hole patterns, it would be a significant advance in the art if a punch unit were devised which could be quickly changed over to a different hole punch pattern.